Chapter 5

Question 1

What are some important characteristics of eukaryotic microorganisms?

Answer 1

• Prominent members of ecosystem
• Useful as model systems and industry
• Some are major human pathogens
• Two groups of eukaryotes commonly posses microbial members including protists and fungi

Question 2

What are the common features of eukaryotic cells?

Answer 2

• Membrane- delimited nucleus
• Membrane bound organelles with specific functions
• Intracytoplasmic membrane complex serves as transport system
• More structurally complex and generally larger than bacterial or archaeal cells

Question 3

Describe eukaryotic cell envelopes.

Answer 3

• Consists of the plasma membrane and all coverings external to it
• Plasma membrane is a lipid bilayer containing phosphoglycerides, sphingolipids, and cholesterol, which contribute to the strength of the membrane
• Microdomains participate in a variety of cellular processes
• Many eukaryotes do not have peptidoglycan or a defined cell wall
• Cell walls of photosynthetic algae have cellulose, pectin, and silica
• Cell walls of fungi consist of cellulose, chitin, and glucan

Question 4

What is the secretory endolytic pathway?

Answer 4

• Intricate complex of membranous organelles and vesicles that move materials into the cell from outside, from inside to outside, and within the cell
• Includes the ER, golgi apparatus, and lysosomes

Question 5

What are the characteristics and functions of the golgi apparatus?

Answer 5

• Membranous organelle made of cisternae stacked on each other
• Cis (forming) and trans (maturing)
• Stack of cisternae is called dictyosomes
• Involved in modification, packaging, and secretion of materials

Question 6

What are the characteristics and functions of lysosomes?

Answer 6

• Membrane- bound organelle found in most eukaryotes
• Involved in intracellular digestion
• Contain hydrolases, which hydrolyze molecules and function best under slightly acidic conditions

Question 7

What are the characteristics and functions of the nucleus?

Answer 7

• Membrane- bound spherical structure that houses genetic material of eukaryotic cell
• Chromosome is composed of chromatin, which is a dense fibrous material

Question 8

How are eukaryotic ribosomes different?

Answer 8

• Larger (more mass) than the 70S bacterial and archaeal ribosomoes
• 80S in size
• 60S + 40S subunits
• May be attached to the ER or free in cytoplasmic matrix
• 60S is bound subunit to ER